I've had a kolsch in primary for 2 weeks at 59 degrees. I want to transfer to a keg and put it in fridge for about a month. Would I need to put an airlock on my keg. I am still getting a few bubbles in my primary now ( haven't taken a gravity reading). I normally use an airlock with secondaries, but don't have any carboys freed up, that is why I am using a keg, just didn't know if airlock was actually needed.